OBJECTIVE:To develop a noninvasive method and device to determine intravariceal pressure and variceal wall tension by measuring the variables of the Laplace equation and test this device in a model of esophageal varices.METHODS:Two variceal pressure measurement devices were constructed. The first device consists of an Olympus 20 MHz ultrasound transducer placed next to a latex balloon catheter attached to a pressure transducer. The second device was constructed by placing the same ultrasound transducer inside a latex condom balloon attached to a pressure transducer. These pressure measurement devices were tested blindly in varix models with different intravariceal pressures, by inflating the balloon to flatten the varix models. Each variceal pressure was measured 10 times by two separate investigators blinded to the actual pressures. The mean intravariceal pressures were calculated. The variceal models were made of a latex balloon filled with water and coffeemate.RESULTS:The correlation coefficient between the actual and measured varix pressures for both devices was 0.99. The percent error ranged from 0 to 10%. The correlation coefficient between the investigators making the blinded measurements for both devices was 0.98.CONCLUSION:Two pressure-measuring devices were developed to determine intravariceal pressure in a model varix system. These devices demonstrate a low percent error and a high correlation to the actual variceal pressures with low intra- and interobserver variability. These devices have the potential to measure all the variables of the Laplace equation for wall tension. We plan to test these devices in human subjects.

Purpose: To localize endoscopic plications with respect to the crural diaphragm (CD) and lower esophageal sphincter in order to determine the physiologic effects of the plication. Methods: Simultaneous ultrasound (US) and manometry was performed with a 20MHz US transducer and a water perfused manometry catheter in 8 patients with GERD before and after endoscopic plication. US images and manometric pressure tracings were synchronized using a kayelemetrics swallowing workstation. The catheter assembly was placed in the stomach and withdrawn through the gastroesophageal junction high pressure zone (GEJHPZ) at a constant velocity of 0.5 cm/sec during breath holding. US images were analyzed for the configuration of the plications, depth of sutures, location of the plications with respect to the CD and changes in the pressure profile. 3D reconstruction of the US images was performed. Results: The plications appear as hypoechoic round structures on 2D US and hypoechoic spherical structures on 3D US. The sutures appear as hyperechoic lines within the plications. The majority of sutures are localized to the submucosa. The majority of the plications were located at or just below the Right Crus of the diaphragm. The distal portion of the pressure profile in the GEJHPZ was lengthened in the area of the plications. Conclusions: 2D and 3D US with simultaneous manometry can be used to localize endoscopic plications, depth of sutures, and changes in the pressure profile pre-and post-Endocinch. Funded through an NIH grant R01 DK59500-03 and C.R. Bard Inc. grant.